1. Field of the Invention
The present invention relates to an adsorptive composition which can adsorb and remove unpleasant odors and/or noxious components (hereinafter referred to as odorous components) in a gas to be treated, and also relates to an adsorptive decomposition composition which can not only adsorb odorous components from the gas but also catalytically decompose those adsorbates desorbed therefrom by heat regeneration.
2. Description of the Prior Art
In order to adsorb and remove odorous components in a gaseous phase, adsorbents such as activated carbon, zeolite, silica gel, alumina, etc. have been used. Methods of decomposing odorous gases by an oxidative decomposition catalyst have been widely employed.
Japanese Patent Public Disclosure No. 53-109874 discloses an apparatus for treatment of odorous gases which comprises an adsorbent which is capable of adsorbing such gases and a catalyst for oxidative combustion of those adsorbates desorbed from the adsorbent in the regeneration thereof. This reference teaches a single layer obtained by sufficiently mixing an adsorbent and a catalyst, a layer in which adsorbent and catalyst layers are stacked alternately, and a filled layer of an adsorbent on which a catalyst metal is deposited to exhibit both activities of adsorption and catalytic oxidation. The reference teaches that adsorbents such as activated carbon, activated alumina, silica gel and zeolite can be used.
Commonly assigned Japanese Patent Application Nos. 1-299533 and 2-89825 disclose an adsorbent which comprises a sepiolite and a catalyst supported thereon. Commonly assigned Japanese Patent Application Nos. 1-270223, 1-282850 and 2-89824 disclose an adsorptive decomposition deodorizer which comprises a sepiolite and catalyst supported thereon. The inventions in accordance with the earlier applications have many advantages such that they preclude any danger of ignition at regeneration, and exhibit excellent adsorptivity and durability, and ease of regeneration. Commonly assigned Japanese Patent Application No. 2-169330 discloses a porous sepiolite which has an improved resistance to water that it will not peptize by soaking it in water and an improved resistance to thermal shock, and a process for producing the same. Commonly assigned Japanese Patent Application No. 2-206481 discloses a porous sepiolite which has an improved adsorptivity and a process for producing the same and an adsorptive decomposition catalyst utilizing such porous sepiolite.
The adsorptive decomposition deodorizer in accordance with the earlier application is suitable for many purposes which vary from large scale treatments such as removal of noxious gases exhausted from factories to small scale treatments such as the removal of odorous gases in a storage compartment of a refrigerator. In order to adapt said adsorption decomposition deodorizer to more various applications, deodorizers having a higher performance are needed. A deodorizer having a larger adsorption rate and adsorption capacity can make the equipment smaller, and an adsorptive decomposition deodorizer which can be regenerated in situ without being taken out of the equipment is able to enlarge the degree of freedom with respect to the design of equipment.